The following discussion of the background to the invention is intended to facilitate an understanding of the invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was published, known or part of the common general knowledge as at the priority date of the application.
Screening apparatus of the type with which the invention is concerned is generally used for screening, grading, or separating materials such as ores and comprises an array of screen panels which are removably fixed to a frame to provide a continuous screen deck. The material to be screened is fed onto the deck at one end and the apparatus is vibrated so that the material moves over and through its screening surface. Some material passes through the panels of the screen deck and is collected below the screen deck. Other material is too large to pass through the panels and remains on top of the screen deck and is collected at the end of the screen deck. That material is kept separate from the material that passes through the screen deck.
One form of screen panel includes a steel frame moulded within a resilient plastic material, such as polyurethane. See for example Australian Patent No. 577767 (66006/86). The plastic moulding forms the major part of the panel and it is in the plastic moulding that the openings for screening are provided.
The screen panels in a screen deck are usually subject to wear, due to the abrasiveness of the mining materials typically being screened, and thus the screens require periodical replacement. This presents a difficulty with the attachment of the panels to the deck frame, as the attachment must be secure and robust, but should also be releasable in a manner that is quick and easy.
The frame to which screen panels in a screen deck are secured usually comprises a framework of elongate beams. The beams can be of various section, but the present invention has been developed for the connection of the screen panels to a top or upstanding edge of a beam.
Applicant has already developed one screen panel fixing system for connecting screen panels to a top or upstanding edge of a beam. That system is described in Australian Patent 2012211453. The system of the present invention is an alternative to the system disclosed in patent 2012211453.